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Artemio Z. Tulio Jr., Kazuo Chachin, Yoshinori Ueda, Kimiko Ose, and Hiroyuki Yamanaka

The physiological and physico-chemical responses of jute, a tropical green leafy vegetable, to several temperature conditions were determined during postharvest storage. Jute were sourced from wholesale market and harvested from the university farm, packed in low-density polyethylene bags and stored at 1 to 30 °C and 1 to 20 °C, respectively, before it was analyzed for postharvest quality changes. There was no significant difference in the time-temperature tolerance of both leaves in all treatments. At 1 °C and 8 °C, both jute showed high sensitivity to chilling injury, which manifested by browning of the stems, darkening of young and mature leaves, wilting, and excretion of slimy substances. These symptoms developed within 3 to 9 days at 1 °C and 5 to 13 days at 8 °C, and it seems related with the decrease of ortho-diphenol content. The chlorophyll fluorescence of jute measured in terms of Fv: Fmax ratio decreased before the onset of browning and remained at lower levels during development of chilling injury at 1 and 8 °C. The ethylene concentration decreased after increasing for 1 day at 8 °C and before chilling injury occurred at 1 °C. However, at 15, 20, and 30 °C, both jute were more susceptible to yellowing with chlorophyll degradation and abscission of leaves due to senescing effect of high-temperature storage. Senescent symptoms were evident within 1 to 5 days at 30 °C and 3 to 7 days at 15 and 20 °C. Jute with stems partly immersed in water during storage had lower respiration rates at 1 and 8 °C due to its sensitivity to chilling injury manifested by wilting of leaves within 1 to 4 days of storage.

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James W. Rushing and Robert F. Testin

Antioxidants and certain variables in the processing protocol were evaluated for their influence on the respiration, ethylene production, color, and storage potential of shredded cabbage (Brassica oleracea L. var. capitata). Four commercially available antioxidants were compared to ascorbic acid and sodium metabisulfite. Compounds were applied either by dipping or by vacuum infusion after the cabbage was shredded. Weight changes occurring during each step of processing were measured. Shredded cabbage was packaged under vacuum in 1.75 mil polyethylene bags and stored at 4°C. In all studies, untreated controls had longer shelf life than any of the treated shredded cabbage based on subjective evaluation as well as objective color scores. Respiration and ethylene production were not influenced by treatment other than centrifugation immediately after shredding, which reduced the rate of both processes by about 50%. Any treatment resulting in weight gain, e.g. vacuum infusion or dipping in aqueous solutions, caused a decrease in shelf life.

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Michael Knee, Peg McMahon, and Glenn Carey

74 POSTER SESSION 8 Postharvest Physiology & Propagation Floriculture & Ornamentals

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Oscar Andrés Del Angel-Coronel, Juan Guillermo Cruz-Castillo, Javier De La Cruz-Medina, and Franco Famiani

Cutting, J.G.M. Wolstenholme, B.N. 1991 Maturity effects on avocado postharvest physiology in fruits produced under cool environmental conditions South African Avocado Growers' Association Yearbook 14 24 26 Dixon

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S.M. Silva and R.M. Beaudry

149 POSTER SESSION 6D (Abstr. 354–370) Postharvest Physiology–Vegetables

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J. Song and R.M. Beaudry

139 ORAL SESSION 32 (Abstr. 227–234) Postharvest Physiology–Fruit II

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Huating Dou, Mohamed A. Ismail, and Peter. D. Petracek

92 POSTER SESSION 10 (Abstr. 105–119) Postharvest Physiology/Storage/Food Science Tuesday, 25 July, 1:00–2:00 p.m.

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Gayle M. Volk, Kate E. Rotindo, and Walter Lyons

Garlic bulbs (Allium sativum L.) harvested in the summer are often stored at room temperature between the time of harvest and curing and either consumption or planting in the fall. The quality of these bulbs usually deteriorates dramatically by 6 months after harvest. Garlic bulbs were placed at -3, 0, or 5 °C for ≈6 months to determine if bulbs could be maintained for spring planting. Response to cold-storage conditions was cultivar dependent. We found that most cured garlic bulbs stored at -3 °C for 6 months successfully formed cloves within bulbs when planted in the following spring. Unlike the high-quality bulbs formed after -3 °C storage, bulbs stored at 0 °C for 6 months often formed side cloves and had loose wrappers. In another study, garlic bulbs stored at 0, 5, 15, or 23 °C exhibited a higher rate of shoot elongation within the cloves during storage than bulbs stored at -3 °C. After 9 months of -3 °C storage, bulbs then held at room temperature retained the quality characteristics of freshly harvested garlic (firmness, taste) for at least 2 months. These studies suggest that cured garlic can be spring planted and consumed year-round when bulbs are stored at -3 °C.

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Sylvia M. Blankenship and L. Eric Hinesley

Fraser fir [Abies fraseri (Pursh) Poir.] branches were held at 5C for 4 to 6 weeks in the following atmospheres: 1% or 3% in nitrogen; 0%, 1%, 5%, 10%, 20%, 40%, or 50% CO2 in air; or air only. Experiments were conducted in two. years during the fall, winter, and early spring. In general, CO2 ≥ 5% accelerated needle loss. There was considerable tree-to-tree variation in tolerance to elevated CO2. Oxygen at 1% killed branches, and 3% O2 showed no benefit compared to air. The initial dark respiration rate at 21C was about four times higher than at SC. Respiration decreased for ≈ 10 days and stabilized at 14% to 20% of the initial values. Respiration increased exponentially with increasing temperature between 5 and 27C. Short-term controlled or modified atmosphere storage would probably not be useful in improving the postharvest handling of Fraser fir.

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A.P. Medlicott, Mayé N'Diaye, and J.M.M. Sigrist

The effects of acetylene at 0, 0.1, 0.2, 0.4, 0.8, or 1.6 ml·liter-1 and exposures of 4, 8, 12, or 24 hours on ripening initiation In mangos (Mangifera indica L.) harvested at three stages of maturity were investigated: Ripeness was assessed before and after treatment in `Tommy Atkins', `Ruby', and `Amelie' mangos by analysis of texture, peel, and pulp color development, soluble solids concentration, and pH. The initiation of ripening depended on the acetylene concentration, exposure time to acetylene, the physiological maturity of the fruit at harvest, and on the cultivar. Changes that can occur during ripening bad different sensitivities to acetylene gas. Acetylene treatment of 0.1 or 0.2 ml·liter-1 for 24 hours at 25C initiated softening, but had no effect on the other ripening processes measured. All the ripening changes measured were initiated with a 24-hour exposure to 0.4 ml·liter-1 in `Tommy Atkins', while 0.8 ml·liter-l was required with `Ruby' mangos. There was an interaction between gas concentration and exposure time taken to Initiate ripening. The 0.8 ml·liter-1 acetylene treatment required 24 hours to initiate full ripening, while 8 hours were required with 1.6 ml·liter-l acetylene and 1.0 ml·liter-1 ethylene. Mature and half-mature fruit showed a similar response to gas treatments; immature fruit failed to show full ripening initiation, although softening and peel color development were enhanced.